Digital quadrature phase correction
AssigneeIntel Corporation
InventorsPraveen Mosalikanti, Nasser Kurd
Life of this patent
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Abstract
Methods and systems to adjust a phase difference between signals, such as to perform quadrature phase correction. First and second signals are digitally compared, such as with exclusive OR circuitry, to provide a comparison signal having a duty cycle representative of a phase difference between the signals. A phase delay of one or both of the first and second signals is adjusted until the duty cycle of the comparison signal corresponds to a desired phase difference. In a clock and data recovery system, the signals may correspond to a zero degree phase of a first phase interpolator and a ninety degree phase of a second phase interpolator, and digital codes to the first and second phase interpolators may be adjusted to provide a fifty percent duty cycle in the comparison signal.
Claims8
A system, comprising:
- first and second phase controllable clock sources to produce respective first and second clock signals;
- a digital comparator to generate a comparison signal having a duty cycle representative of a phase difference between the first and second clock signals;
- a digital controller to adjust a duty cycle of each of the first and second clock signals, and the phase difference between the first and second clock signals, based on the comparison signal;
- a first multiplexer (MUX) to selectively provide the first and second clock signals, and the comparison signal, to the digital controller;
- and
- a calibration system configured to control the first MUX.
Dependencies are inferred from the claim text.